A stent system with a controllable release mechanism

Abstract

The present invention relates to a stent system containing a controllable release mechanism, comprising an elastic stent and a conveying system; the stent is surrounded by a support rod to form a frame, comprising a first support section, an intermediate support section and a second support section; the first support section comprises a controllable release mechanism comprising a release rod, a release hole, a release ring and a release head; the release hole comprises a first release hole, the first release hole is close to the release head and has the largest distance from the closed loop contour surrounded by the distal ends of all release rods; the release rod is located at the proximal end of the first support section and connected to the support rod, the release hole is at the proximal end of the release rod, the release ring is interspersed with the release hole and slidably connected to at least one release hole, and the release head is connected to the release ring; the release head is pulled, all the release holes are closed, and the stent is driven to shrink and be loaded into the conveying system; the second support section and the intermediate support section restore the preset shape, and the first support section restores the preset shape as the release ring relaxes. The present invention realizes controllable release during surgery and is convenient for capture and recovery after complete release, and has high safety.

Description

Technical Field

[0001] The invention relates to the field of passive device treatment of heart failure, and in particular to a stent system containing a controllable release mechanism. Background Art

[0002] Heart failure is the final result of various cardiovascular events and the cumulative effect of various cardiac abnormalities. In some heart diseases, there will be a significant difference in the pressure between the left and right atria. For example, patients with pulmonary hypertension have persistent high right atrial pressure, and the right atrial pressure needs to be reduced, otherwise it will lead to right heart enlargement and right heart failure, and eventually lead to decreased cardiac pumping function. Once cardiovascular patients have clinical manifestations of heart failure, it indicates a poor prognosis. The more severe the heart failure, the higher the risk of death. Heart failure is an abnormal change in cardiac structure and function caused by various reasons, which causes ventricular contraction, ejection and (or) diastolic filling function to be disturbed, thus causing a group of complex clinical syndromes, the main manifestations of which are decreased activity tolerance (dyspnea, fatigue) and fluid retention (pulmonary congestion, systemic congestion and peripheral hematoma).

[0003] Atrial septostomy is a method of treating complex heart diseases. It is an interventional method to establish communication between the left and right atria of the patient, allowing the blood in the left and right atria to mix, adjusting the hemodynamics to a relatively stable state, transferring the pressure between the left and right atria, relieving the heart load, and preventing the patient from experiencing heart failure.

[0004] The V-Wave product, IASD product and the heart failure treatment device mentioned in the patent EP3171786B1 developed abroad are all cutting stents. The waist of these stents can provide a certain support force for the shunt hole after puncture. However, due to the large radial support force and high resilience of the cutting stent, the operator pushes the stent out of the delivery system, gradually stretches it, and finally releases it to the target position. In the process, the stent and the delivery system are usually only connected to each other through simple squeezing to generate friction resistance. At the moment when the stent is completely out of the delivery system, such as the sheath therein, due to the huge deformation of the proximal area of ​​the stent, the adverse event of stent bouncing is very likely to occur. In this case, the stent either forms an impact force on the tissue in the target position area, causing physical damage to the target tissue, or flies to the non-target position area, such as getting stuck in the valve orifice, causing danger to the patient's life; in addition, the products are not provided with a capture structure, resulting in the inability to smoothly and conveniently recover the product in an undesirable position outside the body. This is because when the implantation position of the product is not ideal, or the product falls into the human body due to operator's misoperation, the operator can grab the waist or the edge of the support rod of the left / right disc. Even if the product can be caught, the edge of the support rod of the right / right disc cannot be gathered or is messy after gathering, which greatly increases the size of the sheath required to catch the product. This leads to two situations: 1) The sheath required to catch the product is too large and is not available on the market; 2) If a larger sheath is used directly, it will inevitably cause greater trauma to the patient. Generally speaking, the sheath that intervenes through the body's own vascular channel should be as small as possible, but the clinical recommendation is that the maximum should not exceed 24Fr, especially when the product falls into the pulmonary artery, the required sheath should not exceed 14Fr, otherwise, it will cause trauma to the human body.

[0005] In addition, a controlled release system mentioned in patent CN110934618A may also have the following effects on the implantation process of the atrial septal shunt: a) due to improper operation by the operator, the device may fall from the atrial septal tissue to other locations, such as the right atrium, right ventricle, pulmonary artery, etc.; b) during the implantation of the product, the traction rod at the distal end of the delivery system is located in the right atrium in a scattered lantern shape, which is likely to affect the ultrasound effect; c) the distal end of the delivery system is connected to the product by wire drawing control, which requires the distal end of the traction rod to have a certain rigidity; but the distal end of the traction rod may contact the target tissue of the atrial septum or the right atrial cavity. On the surface, in order to avoid damaging these tissues, the distal area of ​​the traction rod should be flexible, so the distal end of the traction rod cannot reach a so-called "adaptive state"; d) Clinically, this so-called "adaptive state" causes the distal end of the traction rod to be unable to be smoothly retracted into the sheath, which may result in contact with the right atrial tissue and the tissue of the access channel during the withdrawal process, and may even cause damage to certain contacted tissues; e) During the traction process of the controlled release system, the traction force is only transmitted on the traction frame, causing the distal end of the traction rod to undergo elastic deformation, but the traction force cannot be transmitted to the instrument, and it is impossible to accurately judge whether the instrument is safely fixed in the target area on the atrial septum.

[0006] Therefore, the market currently needs to develop a stent system that can be controllably released during surgery and easily captured and retrieved after complete release. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies in the prior art and to provide a stent system containing a controllable release mechanism, so that the stent frame, especially the inner cavity surrounded by the middle support segment, is stable after the stent is implanted in the target tissue, and the stent system can be controllably released during surgery and easily captured and recovered after complete release. Compared with similar products on the market, the stent system has higher safety during and after surgery and is more recyclable.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A stent system with a controllable release mechanism, comprising an elastic stent and a delivery system for delivering the stent to a target position in the body, wherein the stent is framed by support rods, and comprises a first support segment, an intermediate support segment, and a second support segment;

[0010] The stent is a self-expanding structure, the first support segment includes a controllable release mechanism, the controllable release mechanism includes a release rod, a release hole, a release ring and a release head, and the release hole includes a first release hole and a final release hole;

[0011] The release rod is located at the proximal end of the first support section and is fixedly connected to the support rod at the corresponding position, the release hole is fixedly arranged at the proximal end of the release rod, the release ring is sequentially inserted into the release holes to form a closed loop, the release ring is slidably connected to at least one of the release holes, the release head is connected to the release ring, and the release head is detachably connected to the conveying system;

[0012] The bracket has a first form and a second form that can be converted into each other. When the release head is pulled, all the release holes are approached and closed to each other, driving the bracket to shrink. Finally, the entire bracket is linearly loaded or pulled into the conveying system, which is the first form; the second support segment and the middle support segment are successively restored to the preset shape, and then the release rod of the first support segment is restored to the preset shape as the release ring relaxes. The fully stretched state after being fully released to the target position is the second form.

[0013] Preferably, the stent is overall in a flat I-shape, and the stent is an atrial septal puncture stent (that is, an atrial shunt); there is a section α on the edge area of ​​the first support segment; the section α is perpendicular to the central axis m of the stent; there is a section β on the edge area of ​​the second support segment; the section β is perpendicular to the central axis m of the stent.

[0014] Preferably, the first release hole is close to the release head and has the largest distance from a closed loop outline formed by the distal ends of all the release rods.

[0015] Preferably, the release hole, the controllable release mechanism and the bracket are an integrated structure formed by laser engraving and heat setting the same shape memory alloy tube; the number of the release rods is an even number, and is half the number of the support rods on the first support segment; the distal end of the release rod is fixedly connected to the distal end of the corresponding support rod on the first support segment, and the proximal ends of every two adjacent release rods are intersected and fixedly connected to form a release connecting piece, and the point where the proximal ends of every two adjacent release rods intersect is defined as the intersection point, and all the release holes are located on the release connecting piece; on the plane α or the plane β, all the release connecting pieces and the release holes are located within the projection area of ​​the first support segment.

[0016] Preferably, an adaptive structure is provided on the release rod, and the adaptive structure has anatomical adaptability, extending radially outward from the edge of the first support segment, and then extending obliquely across the edge of the first support segment and toward the center of the bracket in a curved shape, and the bending angle θ satisfies: 90°≤θ≤175°; or extending radially outward from the edge of the first support segment, and then extending in a curved shape on plane α in a direction away from the bracket, and the bending angle θ satisfies: 10°≤θ≤135°; the bending angle θ is the angle formed by the radial outward direction of the edge surface of the first support segment and the inward direction of the tangent of the proximal end of the release rod; on plane α or plane β, all the release connectors and the release holes are located in or around the projection area of ​​the first support segment.

[0017] Preferably, the release rod is a thin rod of a shape memory alloy, and the support rod at the edge of the first support segment is the release rod; all the release rods and the bracket are an integrated structure formed by laser engraving and heat setting the same shape memory alloy tube, and the release hole is located at the edge area of ​​the release rod; on the plane α and the plane β, all the release connectors and the release holes are located at the edge of the first support segment.

[0018] Preferably, the release hole includes the first release hole, the second release hole, the third release hole ... the last release hole, the first release hole is at the smallest distance from the central axis of the bracket, and the distances between the first release hole, the second release hole, the third release hole ... the last release hole and the central axis of the bracket are defined as L1, L2, L2', L3, L3' ... L n-1 , L n-1 ', L n , among which L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n Satisfy the mathematical relationship: L1 <L n <L2<L3<……<L n-1 or L1 <L2<L3<……<L n-1 <L n , L2=L2', L3=L3'……L n-1 =L n-1 ', the centers of all the release holes are not on the same circle.

[0019] Preferably, the number of the release holes is at least 4, and the head and tail of the release ring both pass through the first release hole, so that in the second form, the position of the release head relative to the first release hole is limited, and the last release hole includes a double-hole structure, and the release ring is sequentially inserted into the double-hole structure.

[0020] Preferably, on a plane perpendicular to the central axis m and passing through the release hole, the cavity length dimensions of the first release hole, the second release hole, the third release hole... the last release hole are M1, M2, M3... M n , when the release ring is linear, the outer diameter of the release ring itself is M0, then M1, M2, M3... M n satisfy the mathematical relationship: M1 > 2×M0, M2 > 3×M0, M3 > 3×M0... M n-1 > 3×M0, M0 < M n ≤ 3×M0, 0.08mm ≤ M0 ≤ 1mm.

[0021] Preferably, the proximal ends of every two adjacent release rods are joined and fixedly connected to form a release connecting member. The distal end of the release connecting member includes a joining point. The release hole is located on the release connecting member. Except for the central axes of the first release hole and the last release hole passing through the corresponding joining points, the central axes of the remaining release holes do not pass through the corresponding joining points and are located on the side close to the release head; the release hole and the release ring are in an interpenetrating structure. For any one of the release holes, on the side close to the release head, the release ring is above and the release hole is below; on the side far from the release head, the release ring is below and the release hole is above.

[0022] Preferably, the central axis of the release hole forms an angle b with the plane where the proximal regions of the two adjacent release rods are located, satisfying: 0° < b ≤ 90°, and the distance between the surface enclosed by the first release hole and the first support section is the largest.

[0023] Preferably, the release head includes a release head body and a release head neck. The maximum dimension of the release head body is at least the maximum dimension of the release head neck or at least 4 times the wire diameter of the release ring. The central axis of the release head forms an angle γ with the plane enclosed by the support rods in the proximal region of the first support section, satisfying: 5° ≤ γ < 90°, so that the release head body is far from and can protrude from the first support section.

[0024] Preferably, the release head is of a conical or spherical structure and has visibility, and the release head neck abuts against or is close to the first support section.

[0025] Preferably, the angle γ satisfies: 30° ≤ γ ≤ 60°.

[0026] Preferably, a release extension rod is fixedly connected to the proximal end of the first release hole, and an auxiliary release hole is provided at the proximal end of the release extension rod. Both the head and tail of the release ring pass through the auxiliary release hole. In the second form, the position of the release head relative to the auxiliary release hole is limited, and the auxiliary release hole is located between the first release hole and the inner wall of the middle support section.

[0027] Preferably, all outer surfaces of the release rods are wrapped with a winding body, and the winding body is wound around the release connector to form the release hole.

[0028] Preferably, the winding body is formed with a reinforcement structure, and the reinforcement structure is located on the release rod, so that the release connector, the release hole and the release rod are fixedly connected and the relative position of the release hole on the release rod is limited.

[0029] Preferably, the delivery system includes an inner core component, a middle layer component, and a catheter sheath component that can form relative axial movement, the inner core component is detachably connected to the release head, a middle layer tube is provided in the distal area of ​​the middle layer component, and the release ring and the release head can enter and exit the middle layer tube.

[0030] Preferably, it also includes a capture system, which includes a snare, a capture inner sheath and a capture outer sheath, and the release hole, the release ring, the release head, the snare and the capture inner sheath and / or the capture outer sheath cooperate with each other, so that the stent can be captured and removed from the body.

[0031] Preferably, the outer surfaces of the release ring and the release head are covered or wrapped with a biocompatible coating or an anti-thrombotic coating.

[0032] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art:

[0033] 1. The stent system with a controllable release mechanism provided by the present invention, the first support section includes a controllable release mechanism, the controllable release mechanism includes a release rod, a release hole, a release ring and a release head, the release hole includes a first release hole and a final release hole, the release rod is located at the proximal end of the first support section and is fixedly connected to the support rod at a corresponding position, the release hole is fixedly arranged at the proximal end of the release rod, the release ring is sequentially inserted into the release holes to form a closed loop, the release ring is slidably connected to at least one of the release holes, the release head is connected to the release ring, and the release head is detachably connected to the conveying system; the stent It has a first form and a second form that can be converted into each other. When the release head is pulled, all the release holes are moved closer to each other and closed, driving the stent to contract. Finally, the entire stent is linearly loaded or pulled into the delivery system, realizing the functions of pressing and loading the stent into the delivery system. In the process of converting from the first form to the second form, the second support segment and the middle support segment are successively restored to the preset shape, and then the release rod of the first support segment is restored to the preset shape as the release ring relaxes, finally making the stent suitable for percutaneous transcatheter minimally invasive interventional implantation and realizing the controllable release function during the operation.

[0034] 2. The first release hole provided in the present invention is close to the release head and has the largest distance from the closed loop contour formed by the distal ends of all the release rods. This design makes it possible that: when the stent is crimped and loaded into the delivery system, the first release hole enters the delivery system first and is closer to the operator compared to all the release holes. On the one hand, it is avoided to the greatest extent that all the release holes are squeezed together, resulting in individual or most of the release holes being stuck outside the distal end surface of the delivery system, making it difficult to successfully load into the delivery system, and thus failing to ensure that the stent can be easily captured and recovered after being fully released. On the other hand, the area enclosed by the maximum contour of the release hole or the release connector in the circumferential direction is much larger than the cross-sectional area of ​​the corresponding release rod, or the cross-sectional area of ​​the two adjacent release rods. The sum of all the release holes enters the delivery system in a certain order, which can reduce the resistance of the stent and its release holes entering the delivery system (such as the sheath therein) during the process of the stent being converted from the second form to the first form, improve the operator's operating feel, and ensure stronger recyclability. Conversely, it can also make the release process of the stent system safer during the process of converting from the first form to the second form. At the same time, it can reduce the inner diameter of the delivery system, especially the delivery sheath, thereby reducing the requirements for the patient's access route, especially the diameter of the veins (such as the femoral vein, jugular vein) or arteries (such as the femoral artery, carotid artery, radial artery, etc.) during the percutaneous transcatheter minimally invasive interventional implantation of the stent, and to a certain extent expand the scope of application of the stent system products.

[0035] 3. The release holes provided in the present invention include the first release hole, the second release hole, the third release hole...the last release hole, wherein the distances between the first release hole, the second release hole, the third release hole...the last release hole and the central axis of the bracket are defined as L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n , among which L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n Satisfies the mathematical relationship: L1 <L n <L2<L3<……<L n-1 or L1 <L2<L3<……<L n-1 <L n , L2=L2', L3=L3'......L n-1 =L n-1 ', the centers of all the release holes are not on the same circle. This design allows all the release holes to enter the delivery system one by one in a certain order when the stent is crimped and loaded into the delivery system, fundamentally avoiding that all the release holes are squeezed together, resulting in individual or most of the release holes being stuck outside the distal surface of the delivery system, making it difficult to successfully load into the delivery system, thereby ensuring that the stent can be crimped and loaded into the delivery system to achieve a controllable release function, ultimately making the stent suitable for percutaneous transcatheter minimally invasive interventional implantation, and also ensuring the ultra-high safety of the stent being easy to capture and recover after it is fully released.

[0036] 4. The distance between the first release hole and the surface surrounded by the first support segment is the largest, and the remaining release holes are in contact with the surface surrounded by the first support segment, so that most or the entire release ring is in contact with the surface surrounded by the stent. This design has the following advantages: a) reducing the friction between the release ring and the first release hole, so that the first release hole and the release head can quickly and smoothly enter the delivery system, thereby ensuring the loadability of the entire stent and the extremely high safety of easy capture and recovery after complete release; b) reducing the contact area between the stent, especially the first support segment, and the surface in the target position area to a certain extent, thereby minimizing the irritation (and inflammatory response) caused by the stent to the target tissue or organ, especially the surface, and the strict requirements on the anatomical morphology of the target tissue area, thereby expanding the applicable population of the stent system product. For example, when the stent is an atrial septal puncture stent, the product can be applied to the group with a small atrial septum surface area in the right atrium of the heart, especially the oval foramen and the tricuspid valve ring are very close.

[0037] 5. The number of release holes provided in the present invention is at least 4, and the head and tail of the release ring both pass through the first release hole, so that in the second form, the position of the release head relative to the first release hole is limited, which helps the operator to easily manipulate the delivery system to achieve accurate positioning of the stent at the target position, thereby enhancing the controllable release of the stent system. Of course, to a certain extent, it avoids the continuous impact of blood flow on the stent, especially the controllable release mechanism, to form a continuous relative movement, and ultimately causes the endothelialization process of the controllable release mechanism to be slow, or the continuous friction between the release ring and the release hole makes the controllable release mechanism at risk of fatigue fracture. Furthermore, the last release hole includes a double-hole structure, the release ring is sequentially inserted into the double-hole structure, and the length dimension M of the hole cavity of the last release hole is n And the outer diameter of the release ring itself is M0 satisfying: M0 <M n ≤3×M0, 0.08mm≤M0≤1mm, the end release hole is located at the distal end of the release ring, and can be an interference fit with the release ring to fix the release ring, which not only fully ensures that in the second form, the position of the release head relative to the first release hole is limited, but also ensures that after the stent is successively gripped and loaded into the conveying system in vitro, and then released to the target position by the conveying system (the first form is converted to the second form), the relative position of the end release hole and the release ring remains unchanged, thereby ensuring that the release rod of the first support segment can indeed return to the preset shape as the release ring relaxes, and the stent is fully stretched after being fully released to the target position, ultimately ensuring the controllable release, operational safety and convenience of the operation.

[0038] 6. In the present invention, on a plane perpendicular to the central axis m and passing through the release hole, the lengths of the first release hole, the second release hole, the third release hole, ... the last release hole are respectively M1, M2, M3, ... M n When the release ring is linear, the outer diameter of the release ring itself is M0, then M1, M2, M3...M n Satisfy the mathematical relationship: M1>2×M0, M2>3×M0, M3>3×M0……M n-1>3×M0, 0.08mm≤M0≤1mm, this design enables the release ring to form a low-damping slide in the second release hole, the third release hole...the n-1 release hole, and fully reduces the friction resistance between the release ring and the release hole, thereby further improving the function of the stent being pressed and gripped in vitro and loaded into the delivery system, and further ensuring the controllable release, operational safety and convenience of the operation, and further enhancing the safety of easy capture and recovery after complete release. Furthermore, the central axis of the second release hole, the third release hole...the n-1 release hole does not pass through the corresponding intersection point, and is located in the proximal area of ​​the corresponding intersection point. This design enables the release ring to form a nearly unobstructed slide in the second release hole, the third release hole...the n-1 release hole, and minimizes the resistance between the release ring sliding in the release hole, and further enhances the safety and smoothness of easy capture and recovery after complete release.

[0039] 7. The stent system with a controllable release mechanism provided by the present invention also includes a capture system, which includes a snare, a capture inner sheath and a capture outer sheath. Through the cooperation of the release hole, the release ring, the release head, the snare and the capture inner sheath, the stent can be placed in the lumen of the capture outer sheath, recovered and taken out of the body, thereby achieving the capture and recovery of the stent in cases where the release effect is not ideal or it is accidentally dropped. Therefore, compared with similar products on the market, the stent of the present invention is safer and more recyclable. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of a first embodiment of the present invention in which the release hole, the release mechanism and the bracket are an integrated structure, and all the release connectors and the release hole are located outside the projection area of ​​the first support segment;

[0041] Figure 2 This is a schematic diagram of a first embodiment of the present invention in which the release hole, the release mechanism and the bracket are an integrated structure, and all the release connectors and the release hole are located within the projection area of ​​the first support segment;

[0042] Figure 3 for Figure 2 Only the first support segment and the release mechanism, and the top view of the middle support segment are shown;

[0043] Figures 4a to 4c for Figure 3 A partial view of

[0044] Figure 4a for Figure 3 Only a front view of a release hole and its connected release ring is shown;

[0045] Figure 4b for Figure 4a A partial cross-sectional view of the middle release hole and its release ring;

[0046] Figure 4c for Figure 3 Only a partial cross-sectional view of the first release hole, the auxiliary release hole and the release ring thereof is shown;

[0047] Figure 5 This is a schematic diagram of the second implementation mode of the first embodiment of the present invention, wherein the support rod is a release rod, the release hole and the release connector are located at the edge of the first support frame, and the release head is located on the release ring;

[0048] Figure 6 This is a schematic diagram of a second implementation of Example 1 of the present invention, wherein the support rod is a release rod, the release hole and the release connector are located at the edge of the first support frame, and the release head is located at the first release hole;

[0049] Figure 7a to Figure 7b for Figure 6 Partial view:

[0050] Figure 7a is a cross-sectional view of a release head that is conical;

[0051] Figure 7b is a cross-sectional view of a spherical release head;

[0052] Figure 8 It is a schematic diagram of a wrapping body wrapped around a release rod in Embodiment 2 of the present invention;

[0053] Fig. 9 for Figure 8 A schematic diagram showing that the middle release hole and the release connector are a combined structure, and a reinforcement structure is provided on the release rod;

[0054] Fig.10 It is a schematic diagram showing that the stent with a controllable release mechanism in the present invention is in a hollow tubular shape as a whole;

[0055] Fig.11 It is a schematic diagram of the pre-assembly of the stent system containing the controllable release mechanism in the present invention;

[0056] Fig.12a for Fig.10 A partial view of a connection portion in FIG. 1 , wherein the connection method is a threaded connection;

[0057] Figure 12b for Fig.10 A partial view of the connection part in the embodiment, wherein the connection method is a ball head locking connection;

[0058] Fig.12c for Figure 12bThe connection method in the middle is a partial view of the disassembled state;

[0059] Fig.13 It is a schematic diagram of the stent system containing the controllable release mechanism in the present invention being released to the target tissue (atrial septum);

[0060] Fig.14 It is a schematic diagram of the instant when the release head of the stent system with a controllable release mechanism in the present invention is captured by the snare and just enters the capture sheath;

[0061] Fig.15 It is a schematic diagram of a portion of the first support segment of the stent system containing a controllable release mechanism in the present invention being captured in a capture sheath;

[0062] Fig.16 It is a schematic diagram of the instantaneous state in which the stent system with a controllable release mechanism in the present invention is completely captured in the capture outer sheath;

[0063] The reference numerals include: a stent system 1 having a controllable release mechanism; a stent 2; a second support segment 20; an intermediate support segment 21; a support rod 210; an inner cavity 211 of the intermediate support segment; a first support segment 22; a controllable release mechanism 23; a release rod 230; an adaptive structure 2300; a connecting hole C 2301; release connector 2302; intersection point 2303; release hole 231; first release hole 2310; second release hole 2311; third release hole 2312; end release hole 2313; release ring 232; release head 233; release head head 2330; release head neck 2331; winding body 234; reinforcement structure 235; release extension rod 236; auxiliary release hole 237; delivery system 3; inner core assembly 30; middle layer assembly 31; catheter sheath assembly 32; pre-loaded sheath 320; delivery outer sheath 321; capture system 4; snare 40; capture inner sheath 41; capture outer sheath 42; target tissue 5. DETAILED DESCRIPTION

[0064] The technical solution proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In particular, due to the different contents to be highlighted in each drawing, different proportions are often used.

[0065] In order to more clearly describe the stent system with a controllable release mechanism provided by the present invention, the terms "distal end" and "proximal end" are defined herein, and the above terms are conventional terms in the field of interventional medical devices. Specifically, "proximal end" refers to the end close to the operator during the operation, especially when the stent is crimped and loaded in the delivery system, and "distal end" refers to the end away from the operator during the operation, especially when the stent is crimped and loaded in the delivery system.

[0066] The present invention will be further described in detail below with reference to the accompanying drawings and a number of specific embodiments.

[0067] Example 1

[0068] A stent system 1 containing a controllable release mechanism comprises an elastic stent 2 and a delivery system 3 for delivering the stent 2 to a target position in the body; the stent 2 is framed by support rods 210, and specifically, the stent 2 is a wavy or mesh structure formed by a plurality of elastic support rods 210 fixedly connected; the stent 2 comprises a first support segment 22, an intermediate support segment 21 and a second support segment 20 from near to far, and the intermediate support segment 21 is in the shape of a hollow tube.

[0069] The stent 2 is a self-expanding structure. The first support segment 22 includes a controllable release mechanism 23. The controllable release mechanism 23 includes a release rod 230, a release hole 231, a release ring 232 and a release head 233. The release hole 231 includes a first release hole 2310 and a final release hole 2313.

[0070] The release rod 230 is located at the proximal end of the first support section 22 and is fixedly connected to the support rod 210 at the corresponding position. The release hole 231 is fixedly arranged at the proximal end of the release rod 230. The release ring 232 is sequentially inserted into the release holes 231 to form a closed loop. The release ring 232 is slidably connected to at least one of the release holes 231. The release head 233 is connected to the release ring 232. The release head 233 is detachably connected to the conveying system 3.

[0071] The stent 2 has a first form and a second form that can be converted into each other. By pulling the release head 233, all the release holes 231 are moved closer to each other and closed, driving the stent 2 to contract. Finally, the entire stent 2 is linearly loaded or pulled into the conveying system 3. This is the first form of the stent 2, so the function of the stent 2 being pressed and loaded into the conveying system 3 is realized; in the process of converting from the first form to the second form, the second support segment 20 and the middle support segment 21 are successively restored to the preset shapes, and then the release rod 230 of the first support segment 22 is restored to the preset shape as the release ring 232 relaxes. The fully stretched state after being fully released to the target position is the second form of the stent 2, which finally makes the stent 2 suitable for percutaneous transcatheter minimally invasive interventional implantation and realizes the controllable release function during the operation.

[0072] Preferably, the first release hole 2310 is close to the release head 233 and is at the maximum distance from the closed loop contour formed by the distal ends of all the release rods 230. This design makes it possible that: when the stent 2 is pressed and loaded into the delivery system 3, the first release hole 2310 enters the delivery system 3 first and is closer to the operator compared to all the release holes 231. On the one hand, it is avoided to the greatest extent that all the release holes 231 are squeezed together, resulting in individual or most of the release holes 231 being stuck outside the distal end surface of the delivery system 3, making it difficult to successfully load into the delivery system 3, and thus failing to ensure that the stent 2 can be easily captured and recovered after being fully released. On the other hand, due to the circumferential direction of the release holes 231 or the release connector 2302 The area enclosed by the maximum contour is much larger than the cross-sectional area of ​​the corresponding release rod 230, or the sum of the cross-sectional areas of two adjacent release rods 230. All the release holes 231 enter the delivery system 3 in a certain order, which can reduce the resistance of the stent 2 and its release holes 231 entering the delivery system 3 (such as the sheath therein) during the process of the stent 2 being converted from the second form to the first form, improve the operator's operating feel, and ensure stronger recyclability. Conversely, it can also make the release process of the stent system safer during the conversion from the first form to the second form. At the same time, it can reduce the inner diameter of the delivery system 3, especially the delivery sheath 321, thereby reducing the requirements for the patient's access, especially the diameter of the veins (such as the femoral vein, jugular vein) or arteries (such as the femoral artery, carotid artery, radial artery, etc.) of the percutaneous transcatheter minimally invasive interventional implantation of the stent 2, and to a certain extent expand the scope of application of the stent system product.

[0073] In one embodiment, the release hole includes the first release hole, the second release hole, the third release hole...the last release hole, the first release hole is at the smallest distance from the central axis of the bracket, and the first release hole, the second release hole, the third release hole...the distances between the last release hole and the central axis of the bracket are defined as L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n , among which L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n Satisfy the mathematical relationship: L1 <L n <L2<L3<…… <L n-1 or L1 <L2<L3<……<L n-1 <L n , L2=L2', L3=L3'……L n-1 =L n-1', the centers of all the release holes are not on the same circle, and this design has the following advantages: 1) The distance between the first release hole 2310 and the central axis of the stent 2 is the smallest, so that the release head 233 is closer to the center position of the stent 2. When the stent 2 is pressed and loaded into the delivery system 3, compared with all the release holes 231, the first release hole 2310 enters the delivery system 3 first and is closer to the operator. a) All the release holes 231 can enter the delivery system 3 one by one in a certain order, fundamentally avoiding all the release holes 231 from being squeezed together, resulting in individual or most of the release holes 231 being stuck outside the distal end surface of the delivery system 3, making it difficult to successfully load into the delivery system 3, thereby ensuring that the stent 2 can be pressed and loaded into the delivery system 3, realizing the controllable release function, and finally making the stent 2 suitable for percutaneous transcatheter minimally invasive interventional implantation, and also ensuring the ultra-high safety of the stent 2 that is easy to capture and recover after it is completely released; b) Due to the release holes 231 or the maximum contour of the release connector 2302 in the circumferential direction is much larger than the sum of the cross-sectional areas of the two adjacent release rods 230. All the release holes 231 enter the delivery system 3 in a certain order, which can reduce the resistance of the stent 2 and its release holes 231 entering the delivery system 3 (such as the sheath therein) during the conversion of the stent 2 from the second form to the first form, improve the operator's operating feel, and ensure stronger recyclability; c) it can make the release process of the stent system safer during the conversion from the first form to the second form; 2) reduce the inner diameter of the delivery system 3, especially the delivery sheath 321, thereby reducing the requirements of the percutaneous transcatheter minimally invasive interventional implantation of the stent 2 on the patient's access, especially the diameter of the vein or artery, and to a certain extent expand the scope of application of the product.

[0074] In one embodiment, the distance between the first release hole 2310 and the surface surrounded by the first support section 22 is the largest, and the remaining release holes 231 are in contact with the surface surrounded by the first support section 22, so that most or the entire release ring 232 is in contact with the surface surrounded by the bracket 2. This design has the following advantages: a) reducing the friction between the release ring 232 and the first release hole 2310, facilitating the first release hole 2310 and the release head 233 to quickly and smoothly enter the conveying system 3, thereby ensuring the loadability of the entire bracket 2 and the extremely high safety of catching and recovering after complete release; b) To a certain extent, the contact area between the stent 2, especially the first support segment 22, and the surface in the target position area is reduced, and the stimulation (and inflammatory response) caused by the stent 2 to the target tissue 5 or organ, especially the surface, and the stringent requirements on the anatomical morphology of the target tissue 5 area are minimized, thereby expanding the applicable population of the stent system. For example, when the stent 2 is an atrial septal puncture stent 2, the product can be applied to a group of people with a small atrial septum surface area in the right atrium of the heart, especially a group with a close distance between the oval foramen and the tricuspid valve ring; c) to a certain extent, the space occupied by the first support segment 22 in the right atrium is reduced, and the operating space is increased during the implantation of the stent system, while also reducing the impact on cardiac hemodynamics;

[0075] In one embodiment, the number of the release holes 231 provided in the present invention is at least 4, and the head and tail of the release ring 232 both pass through the first release hole 2310, so that in the second form, the position of the release head 233 relative to the first release hole 2310 is limited, which helps the operator to easily manipulate the delivery system 3 to achieve precise positioning of the stent 2 at the target position, thereby enhancing the controllable releasability of the stent system in the present invention. Of course, to a certain extent, it is possible to avoid blood flow constantly impacting the stent 2, especially the controllable release mechanism 23, resulting in continuous relative movement, and ultimately causing the endothelialization process of the controllable release mechanism 23 to be slow, or the release ring 232 and the release hole 231 are constantly rubbed, causing the controllable release mechanism 23 to be at risk of fatigue fracture. Furthermore, when the number of the release holes 231 is an even number, the last release hole 2313 includes a double-hole structure, and the release ring 232 is sequentially interspersed with the double-hole structure, such as Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, it is ensured that both ends of the release ring 232 can pass through the first release hole 2310 from bottom to top, so as to facilitate the controllable release of the bracket 2 and the subsequent capture and recovery by means of the release head 233. The hole length M of the end release hole 2313n The outer diameter M0 of the release ring 232 satisfies: M0 <M n ≤3 ×M0, 0.08mm≤M0≤1mm, the end release hole 2313 is located at the distal end of the release ring 232, and can be an interference fit with the release ring 232, thereby fixing the release ring 232. This not only fully ensures that in the second form, the position of the release head 233 relative to the first release hole 2310 is limited, but also ensures that after the stent 2 is successively gripped and loaded into the conveying system 3 in vitro, and is released to the target position by the conveying system 3 (the first form is converted into the second form), the relative position of the end release hole 2313 and the release ring 232 remains unchanged, thereby ensuring that the release rod 230 of the first support segment 22 can restore to a preset shape as the release ring 232 relaxes, and the stent 2 is in a fully stretched state after being fully released to the target position, ultimately ensuring the controllable release, operational safety and convenience of the operation.

[0076] In one embodiment, on a plane perpendicular to the central axis m and passing through the release hole 231, the lengths of the cavities of the first release hole 2310, the second release hole 2311, the third release hole 2312, ..., the last release hole 2313 are M1, M2, M3, ..., respectively. n When the release ring 232 is linear, the outer diameter of the release ring 232 itself is M0, then M1, M2, M3...M n Satisfy the mathematical relationship: M1>2×M0, M2>3×M0, M3>3×M0…M n-1 >3×M0, 0.08mm ≤M0≤1mm. This design allows the release ring 232 to form a low-damping sliding in the second release hole 2311, the third release hole 2312...the n-1th release hole, thereby fully reducing the friction resistance between the release ring 232 and the release hole 231. Therefore, it not only further improves the function of the stent 2 being gripped in vitro and loaded into the delivery system 3, but also further ensures the controllable release, operational safety and convenience of the operation, and further enhances the safety of catching and recovering after complete release. Furthermore, the central axes of the second release hole 2311, the third release hole 2312 ... the n-1th release hole do not pass through the corresponding intersection 2303, and are located on the side close to the release head 233. This design enables the release ring 232 to slide almost unimpeded in the second release hole 2311, the third release hole 2312 ... the n-1th release hole, thereby minimizing the resistance of the release ring 232 sliding in the release hole 231, and further enhancing the safety and smoothness of capture and recovery after complete release.

[0077] The aperture of the first release hole 2310 is as large as possible within the range allowed by the size of the release connector 2302 to ensure that the two end heads of the release ring 232 can slide smoothly in the first release hole 2310, but does not exceed the size of the release head 233 to ensure that the release head 233 can protrude from the outer surface of the controllable release mechanism 23 and make the release head 233 completely close to the first release hole 2310.

[0078] Preferably, the release hole 231 and the release ring 232 are interlaced structures. For any one of the release holes 231, on the side close to the release head 233, the release ring 232 is on the top and the release hole 231 is on the bottom; on the side away from the release head 233, the release ring 232 is on the bottom and the release hole 231 is on the top.

[0079] For the stent 2 with the controllable release mechanism provided by the present invention, in one embodiment, the stent 2 is mostly or entirely in the shape of a hollow tube, and the outer contour of such a hollow tube includes a straight cylindrical shape with equal diameter, such as Fig.10 As shown, the stent 2 has an equal diameter but curved arched cylindrical shape, a gradually changing cone or truncated cone shape. This type of stent 2 can be adapted to the inner cavity of various arteries or veins, and is used for supporting various large and small blood vessels such as coronary arteries (coronary artery stents), peripheral popliteal arteries (popliteal artery stents) and below-the-knee arteries (below-the-knee artery stents), intracranial arteries (intracranial artery covered stents), and jugular veins (jugular vein stents) to treat vascular stenosis or blockage. It can also be used for the isolation or occlusion of true aneurysms or false aneurysms (such as abdominal aortic covered stents) formed by dissection ruptures of peripheral blood vessels (thoracic aortic covered stents) or vascular enlargement, to prevent vascular rupture. Of course, it can also be used for filtering or accommodating debris such as arteriovenous thrombosis or calcification, such as venous thrombosis filters, arterial thrombosis protectors, etc., to prevent blockage of blood vessels supplying important organs of the human body.

[0080] In another embodiment, the stent 2 is in a flat I-shape as a whole, and the stent 2 is an atrial septal stent 2 (i.e., an atrial shunt). Specifically, the stent 2 includes a first support segment 22 that fits the atrial septum surface in the right atrial cavity, a second support segment 20 that fits the atrial septum surface in the left atrial cavity, and an intermediate support segment 21 that is disposed between the first support segment 22 and the second support segment 20 and fixedly connects the first support segment 22 and the second support segment 20. There is a section α on the edge area of ​​the first support segment 22, and the section α is perpendicular to the central axis m of the stent 2. There is a section β on the edge area of ​​the second support segment 20, and the section β is perpendicular to the central axis m of the stent 2. This design can significantly enhance the fit between the edge area of ​​the second support segment 20 and the edge area of ​​the first support segment 22 and the target tissue 5, and reduce the stimulation or damage to the target tissue 5 by the edge area of ​​the second support segment 20 and the edge area of ​​the first support segment 22 to a certain extent. The middle support section 21 is in the shape of a hollow tube as a whole. The inner cavity of the middle support section 21 enables the left atrium and the right atrium to form a fluid connection, thereby achieving flow shunt between the left atrium and the right atrium.

[0081] The following content further elaborates and illustrates the stent system for establishing atrial shunt after atrial septal puncture.

[0082] In this embodiment, the release rod 230 and the release hole 231 of various implementations are arranged on the first support section 22. The release hole 231, the controllable release mechanism 23 and the bracket 2 are an integrated structure formed by laser engraving and heat setting of the same shape memory alloy tube.

[0083] In the first embodiment, the number of the release rods 230 is an even number, and is half the number of the support rods 210 on the first support segment 22. The distal end of the release rod 230 is fixedly connected to the distal end of the support rod 210 on the corresponding first support segment 22, and the proximal ends of each two adjacent release rods 230 intersect and are fixedly connected to form a release connector 2302. The point where the proximal ends of each two adjacent release rods 230 intersect is defined as an intersection point 2303, and all the release holes 231 are located on the release connector 2302. On the plane α or the plane β, all the release connectors 2302 and the release holes 231 are located in the projection area of ​​the first support segment 22, such as Figure 2 This design has the following advantages:

[0084] a) The release holes 231 are located within the area covered by the first support segment 22, that is, the area of ​​the circle surrounded by all the release holes 231 is smaller than the area covered by the first support segment 22, and the release ring 232 is located outside the lumen surrounded by the middle support segment 21, and does not affect the diversion effect of the lumen surrounded by the middle support segment 21;

[0085] b) reducing the diameter of the circle formed by the distal ends of all the traction rods detachably connected to the release connector 2302 in the prior art, that is, reducing the space occupied by the traction rods in the right atrium to a certain extent, increasing the operating space during the implantation of the stent system, and also reducing the impact on cardiac hemodynamics;

[0086] c) Compared with the prior art, the number of release rods 230 is reduced so that the number of release rods 230 is half of the number of support rods 210 on the first support segment 22. This method makes it easier to control the traction process of the stent system, which helps the operator to fully judge whether the stent system is safely fixed (straddling) on ​​the target atrial septum tissue 5 through a traction test.

[0087] In addition, the release rod 230 is provided with an adaptive structure 2300, and the adaptive structure 2300 is located in the connection area between the release rod 230 and the support rod 210 of the first support section 22. The adaptive structure 2300 extends radially outward from the edge of the first support section 22, and then extends obliquely across the edge of the first support section 22 and toward the center of the support frame in a curved shape ( Figure 2 ), the bending angle θ of the adaptive structure 2300 satisfies: 90°≤θ≤175°, or extends radially outward from the edge of the first support segment 22 and then extends in a curved shape on the plane α in a direction away from the support frame ( Figure 1 ), the bending angle θ of the adaptive structure 2300 satisfies: 10°≤θ≤135°, wherein the bending angle θ is the angle formed by the radial outward direction of the edge surface of the first support segment 22 and the outward direction of the tangent of the proximal end of the release rod 230.

[0088] Preferably, the adaptive structure 2300 extends radially outward from the edge of the first support segment 22, then crosses the edge of the first support segment 22 in a curved shape and extends toward the center of the support frame, and the bending angle θ of the adaptive structure 2300 satisfies: 90°≤θ≤175°. The adaptive structure 2300 has the following advantages:

[0089] a) having a large curved arc and tending to be flat, which greatly increases the contact area between the stent 2 and the target tissue 5, minimizes the stimulation and damage of the stent 2 to the target tissue 5, and avoids the stimulation and inflammatory response to the tissue and physical damage to the tissue due to mechanisms such as stress concentration;

[0090] b) The adaptive structure 2300 as described above also has the characteristic of being close to the outer surface of the first support segment 22 and not being obtrusive relative to the first support segment 22, thereby reducing the space occupied in the right atrium and greatly reducing the impact on hemodynamics; at the same time, the probability of thrombosis on the stent 2 is reduced;

[0091] c) relative to all the support rods 210 in the edge area of ​​the first support segment 22, the adaptive structure 2300 has a much smaller cross-sectional area and a much higher elastic deformability, wherein the cross-sectional area of ​​the adaptive structure 2300 does not exceed half of the cross-sectional area of ​​all the support rods 210; I) not only enables all the adaptive structures 2300 to have a certain degree of radial telescopic adjustment function, so that they can adapt to a smaller surface area of ​​the atrial septum, expanding the applicable population of the stent system of the present invention, especially the Asian population, and the minor population; of course, the influence on the adjacent tissues of the atrial septum, such as the tricuspid valve, can also be minimized or controlled; II) also enables the adaptive structure 2300 to have a certain degree of elastic deformability in the axial direction, so that it can adapt to the uneven tissue that may exist in the right atrial side area of ​​the atrial septum, significantly increase tissue adhesion, and reduce the stimulation and damage of the stent 2 to the target tissue 5, so that it has a wide range of anatomical morphological adaptability;

[0092] d) Although the release rod 230 has an adaptive structure 2300, the pressure transmission of the stent 2 during the whole process of being pressed and gripped in the delivery sheath and pushed to the target position and the tension transmission of the stent 2 after being partially or completely released and recovered or captured into the delivery sheath are not lost, thus giving the stent system super high maneuverability during surgical introduction, recovery or capture. Compared with the traditional atrial septal defect occluder, this surgical method has almost the same surgical method and surgical steps, so the product has a short learning curve (cycle) and fast application and popularization; in order to prevent the pressure transmission from being lost, the curve length of the adaptive structure 2300 is 1 to 15 mm, preferably, the length of the adaptive structure 2300 is 2 to 5 mm;

[0093] e) The adaptive structure 2300 obliquely crosses the edge of the first support section 22 and extends towards the center of the stent 2, causing the release lever 230 to move closer to the proximal end and the central region, and the release connection member 2302 is always located outside the proximal end of the first support section 22. This facilitates the operator to use the release head 233 and the release loop 232, in cooperation with the snare 40 and the capture sheath, to perform the function of retrieving the stent 2 into the sheath after capture. It will not occur that attempting to tighten the release loop 232 may directly cause the edge of the support rod 210 of the first support section 22 to radially contract, and then overwhelm the periphery of the intermediate support section 21, resulting in partial or complete overlap of the support rod 210, especially the edge, of the first support section 22 with the support rod 210 of the intermediate support section 21. Furthermore, a circular bulge is formed in the connection transition region between the intermediate support section 21 and the first support section 22. Since the outer diameter of the circular bulge is very large, it may exceed 20 mm, resulting in the inability to finally retrieve it into the capture sheath used in the subsequent mentioned conventional surgery. Therefore, when the stent system is completely released to the atrial septal target tissue 5, if there is instrument displacement or insufficient effectiveness of the pore formation, and it may be due to improper operation of the operator, causing the instrument to fall from the atrial septal tissue to other positions, such as the right atrium, right ventricle, pulmonary artery, etc., this design of the adaptive structure 2300 enables the operator to promptly carry out emergency remedial measures, facilitates the implementation of the capture and retrieval function, and safely and quickly retrieves the stent 2 into the sheath until it is removed from the patient's body, ultimately ensuring very high safety of the surgery.

[0094] Preferably, the central axis of the release hole 231 forms an angle b with the plane where the proximal regions of two adjacent release levers 230 are located, and the angle b satisfies: 0° < b ≤ 90°, so that the surface enclosed by the release hole 231 and the first support section 22 can be maximally fitted.

[0095] In the second embodiment, the release lever 230 is a shape memory alloy thin rod, and the support rod 210 at the edge of the first support section 22 is the release lever 230, as Figure 5 and Figure 6 shown. All the release levers 230 and the support frame are an integral structure formed by laser engraving and heat setting from the same shape memory alloy tube, and the release hole 231 is located in the edge region of the release lever 230. On the plane α and the plane β, all the release connection members 2302 and the release holes 231 are located at the edge of the first support section 22, but the centers of all the release holes 231 are not on the same circle. This design has a simple structure, is easy to manufacture, and can also achieve beneficial effects close to those of the first embodiment.

[0096] Preferably, the release head 233 is located at the first release hole 2310, and both the head and tail of the release ring 232 pass through the first release hole 2310, so that in the second form, the position of the release head 233 relative to the first release hole 2310 is limited.

[0097] In one embodiment, the proximal end of the first release hole 2310 is also fixedly connected to a release extension rod 236, and the proximal end of the release extension rod 236 is provided with an auxiliary release hole 237. The release extension rod 236, the auxiliary release hole 237 and the support 2 are an integrated structure formed by laser engraving and heat setting of the same shape memory alloy tube, and the release ring 232 is a closed loop structure formed by heat setting of a shape memory alloy wire; both the head and tail of the release ring 232 pass through the auxiliary release hole 237, and the auxiliary release hole 237 is located between the first release hole 2310 and the inner wall surface of the middle support section 21, as shown in FIG. Figure 4c As shown, in the second form, the position of the release head 233 relative to the auxiliary release hole 237 is limited. This design can reduce the distance between the release head 233 and the central axis of the stent 2, thereby making the release head 233 closer to the central area of ​​the proximal end of the stent 2, thereby facilitating the loading and sheathing of the stent 2 and improving the safety of the operation process.

[0098] As for the release ring 232, the release ring 232 passes through all the release holes 231 in sequence in an up-and-down interlaced manner, and the two ends of the release ring 232 are gathered at the release head 233. Figure 5 , Figure 6 As shown, the release head 233 is placed in the release head 233 by thread extrusion, knotting, heat welding, gluing, etc. to form a closed loop structure, so that the release head 233 is close to the release hole 231 and protrudes from the outer surface of the first support segment 22.

[0099] In one embodiment, the release ring 232 is made of a flexible material. In a natural state, the shape of the release ring 232 is the same as or close to the shape of the polygon formed by the release hole 231, so that the release ring 232 is in a taut state. The release heads 233 located at both ends of the release ring 232 are relatively fixed in position with the release ring 232, close to and protruding from the outer surface of the release mechanism or the first support section 22.

[0100] In another embodiment, the release ring 232 is made of a same metal wire with elasticity, shape memory or torsion resistance, connected end to end to form a ring. Considering the smoothness of the metal wire sliding through the release hole 231, the wire diameter of the metal wire is preferably controlled within and When the release ring 232 is visible, such as using a shape memory alloy wire, the operator can judge the position and state of the stent 2 through the image, thereby achieving the release and recovery operation of the stent 2; in a natural state, the two end areas of the release ring 232 are gathered and shaped, and are located at the edge of the release mechanism or the first support segment 22. Preferably, the two end heads of the release ring 232 are located at the release hole 231, so that the release head 233 is close to the release hole 231 and protrudes from the outer surface of the release mechanism or the first support segment 22.

[0101] The release ring 232 passes through all the release holes 231 in sequence in an up-and-down interlaced manner, thereby forming a closed-loop structure. The shape of the closed loop should preferably be circular, which can ensure that the area enclosed by the release ring 232 is not less than the polygonal area enclosed by the release holes 231 passed through, and is located within the area covered by the first support segment 22. When the number of release holes 231 is small, such as 4, the shape of the closed loop line may be a quadrilateral, which causes part of the line segments of the closed loop line to be located within the area covered by the inner cavity 211 of the middle support segment, affecting the shunting effect to a certain extent and increasing the risk of forming thrombus on the surface of the stent 2. Preferably, the figure enclosed by the release ring 232 passing through each two adjacent release holes 231 is a two-dimensional or three-dimensional circular arc or V-shaped wave. This design enables the release ring 232 to bypass the projection area of ​​the middle support segment 21 on the plane α without affecting the shunting effect of the stent 2.

[0102] Further preferably, an arc-shaped transition structure is provided in the wave point area of ​​the V-shaped wave, and the arc-shaped transition structure usually has an arc radius of 1 to 15 mm. This design does not affect the relative sliding of the release rod 230 and the release hole, thereby ensuring that the release and deployment process of the first support segment 22 and the capture and recovery process of the bracket 2 are not affected.

[0103] Preferably, the outer surfaces of the release ring 232 and the release head 233 are provided with a coating, such as polyparaxylene, titanium nitride, mucopolysaccharide sulfate, ceramic, polyethylene terephthalate, expanded polytetrafluoroethylene, polyurethane, heparin, and the outer surfaces of the release ring 232 and the release head 233 are covered by coating or magnetron sputtering. The coating has a thickness of 0.05 to 10 μm, which can effectively enhance the adhesion of the coating to the surface of the metal material, and can perform surface modification on the metal material implanted in the human body for a long time to improve its corrosion resistance and reduce the risk of thrombosis.

[0104] Preferably, the release head 233 is visible so as to facilitate rapid identification and location of the connection between the release head 233 and the release rod 230 with the aid of imaging equipment, such as ultrasound or X-ray equipment.

[0105] Preferably, the release head 233 is a conical or spherical structure, such as Figure 7a , Figure 7b As shown, structurally, the release head 233 includes a release head head 2330 and a release head neck 2331, the release head neck 2331 is close to or close to the first support segment 22, the maximum size of the release head head 2330 is at least the maximum size of the release head neck 2331 or at least 4 times the wire diameter of the release ring 232, and the release head head 2330 is away from and can protrude from the first support segment 22. In addition, the central axis of the release head 233 and the surface enclosed by the support rod 210 in the proximal region of the first support segment 22 form an angle γ, and the angle γ satisfies 5°≤γ<90°. This design can take into account both the convenience of recovery and the risk of reducing thrombosis after multiple tests simulating clinical environments. More preferably, the angle γ should satisfy 30°≤γ≤60°, so that the snare 40 mentioned later can quickly capture the release head and neck 2331, and through the mutual cooperation with the capture inner sheath 41 and the capture outer sheath 42 mentioned later, the stent 2 can be recovered into the capture outer sheath 42.

[0106] Preferably, a stepped hole is provided at the distal end of the release head neck 2331, the size of the stepped hole decreases from near to far, and the stepped hole can accommodate the end of the release rod 230; the size of the end of the release rod 230 is larger than the minimum aperture size of the stepped hole, so as to realize the limiting connection between the release rod 230 and the release head 233. Furthermore, the minimum aperture of the stepped hole can pass through the two ends of the release rod 230 at the same time, so that in the process of the snare 40 mentioned later capturing the release head 233, the end of the release rod 230, especially the part outside the release head 233 and adjacent to the release head 233, can play the role of the neck, so that the snare 40 can capture and firmly cover the release head 233, thereby avoiding the snare 40 and the bracket 2 from slipping during the capture process, causing the bracket 2 to fall off.

[0107] Preferably, the release head head 2330 and the release head neck 2331 can be fixedly connected by threaded connection, adhesive connection, welding or mechanical clamping. As a further preferred embodiment, the proximal end of the release head and neck 2331 is provided with an internal thread, and the distal end of the release head portion 2330 is provided with an external thread. Through the matching connection between the threads, not only can the release head and neck 2331 and the release head portion 2330 be fixedly connected, but also the internal space of the proximal end of the release head and neck 2331 and the distal end of the release head portion 2330 can be limited. By thread extrusion, the two end portions of the release rod 230 are completely placed inside the release head 233. This design ensures that the positions of the two end portions of the release rod 230 in the release head 233 are not affected by the release process and the recovery operation, and are always located inside the release head 233 and do not contact with blood, thereby reducing the risk of thrombosis. The delivery system 3 at least includes an inner core assembly 30, and the proximal end of the release head portion 2330 is provided with an internal thread. The proximal end of the internal thread is detachably connected to the distal end of the inner core assembly 30 of the delivery system 3 through a threaded connection.

[0108] Example 2

[0109] Based on Example 1, Example 2 is different from the first embodiment in Example 1 in that: the release hole 231 and the release connector 2302 are combined, and the entire outer surface of the release rod 230 is wrapped with a winding body 234, such as Figure 8 As shown, the release hole 231 is formed by the winding body 234 winding at the release connector 2302, and the release hole 231 has flexibility and anti-extension. The release ring 232 passes through all the release holes 231 in sequence in an up-and-down interlaced manner, and the two ends of the release ring 232 are gathered at the release head 233, and are placed in the release head 233 by thread extrusion, knotting, heat welding, gluing, etc. to form a closed loop structure. The release head 233 can protrude from the outer surface of the release mechanism and is detachably connected to the conveying system 3.

[0110] Preferably, the release rod 230 is provided with a connection hole C 2301. Furthermore, the connection hole C 2301 is located inside the release rod 230, which facilitates the two ends of the winding body 234 to pass through the connection hole C 2301 respectively, and to be wound around the release rod 230, and to completely wrap the release rod 230. This design has the following advantages:

[0111] a) The connection hole C 2301 can fix the two ends of the winding body 234 to prevent the winding body 234 from slipping during the loading and recovery process of the bracket 2;

[0112] b) The wrapping body 234 completely wraps the release rod 230, reducing the surface area of ​​direct contact between metal and blood in the product, and also reducing the risk of complications such as thrombus formation on the product surface;

[0113] c) The winding body 234 preferably uses a material with a lower friction coefficient than that of the release rod 230, such as polytetrafluoroethylene, expanded polytetrafluoroethylene, and fluorinated ethylene propylene. This can not only reduce the friction resistance of the stent 2 entering and exiting the delivery system 3 and the subsequently mentioned capture sheath 42 during installation or release, but also improve the operating feel and ensure the controllability of installation and release. At the same time, when a material with a porous structure is used as the winding body 234, it is beneficial to the tissue growth and endothelial coverage on the release rod 230 after the stent 2 is released on the target tissue 5, shortening the endothelialization time and enhancing the fixation security of the stent 2.

[0114] Preferably, the winding body 234 is formed with a reinforcement structure 235, such as Fig. 9 As shown, the reinforcement structure 235 is located on the release rod 230, so that the release connecting piece 2302, the release hole 231 and the release rod 230 are fixedly connected, so as to prevent the winding body 234 from relatively slipping on the release rod 230 under the action of external force, ensure the stability of the size of the release hole 231, and limit the relative position of the release hole 231 on the release rod 230.

[0115] Example 3

[0116] Based on Example 1, Example 3 is different from Example 1 in that: the delivery system 3 at least includes an inner core component 30, a middle layer component 31 and a catheter sheath component 32 that can form mutual axial movement. The inner core component 30 can move axially in the inner cavity of the middle layer component 31, and the distal end of the inner core component 30 is detachably connected to the release head 233. Specifically, the proximal end of the release head 2330 is provided with an internal thread, and the proximal end of the internal thread is detachably connected to the distal end of the inner core component 30 through a threaded connection ( Fig.12a ), or the release head 233 and the distal end of the inner core assembly 30 are connected by a ball head to achieve detachable ( Figure 12b , Fig.12c ). The distal region of the middle layer component 31 is provided with a middle layer tube, and the release ring 232 and the release head 233 can enter and exit the middle layer tube. The catheter sheath component 32 includes a pre-installed sheath 320 and a delivery sheath 321. In this embodiment, the release and recovery process of the delivery system 3 and the stent 2 is simpler and safer, and the specific implementation process is as follows:

[0117] The stent 2 and the inner core assembly 30 are preassembled in vitro, and the preassembly process is as follows:

[0118] a) First, the bracket 2 is detachably connected to the distal end of the inner core component 30 by threaded engagement, then, the proximal handle of the inner core component 30 is withdrawn, and the release head 233 and the end of the release ring 232 and the part of the release ring 232 adjacent to the release head 233 are put into the middle layer component 31, and the middle layer component 31 and the inner core component 30 are relatively fixed by the locking device of the proximal handle of the middle layer component 31;

[0119] b) further pulling back the inner core assembly 30, and completely compressing and loading the stent 2, including the first support segment 22, the middle support segment 21, and the second support segment 20, into the preloaded sheath 320, as shown in FIG. Fig.11 shown.

[0120] Then, the pre-installed stent system is used in conjunction with the delivery sheath 321 to complete the implantation of the stent 2. The specific process is as follows:

[0121] a) After the channel is established in the body, the distal end of the delivery sheath 321 is located at the target position of the atrial septum. At this time, the distal end of the preloaded sheath 320 is inserted into the proximal end of the delivery sheath 321, and the middle layer component 31 is slowly pushed to the distal end to introduce the stent system into the delivery sheath 321;

[0122] b) The position of the delivery sheath 321 remains unchanged, and the middle layer component 31 is slowly pushed toward the distal end until the second support segment 20 of the stent 2 is pushed to the outside of the distal end of the delivery sheath 321 and is fully stretched;

[0123] c) slowly withdrawing the delivery sheath 321 toward the proximal end so that the second support segment 20 can be attached to the target tissue 5 on the left atrial side of the atrial septum;

[0124] d) After the second support segment 20 is completely in contact with the target tissue 5, the delivery sheath 321 is continuously withdrawn toward the proximal end, so that the intermediate support segment 21 and the first support segment 22 are located outside the delivery sheath 321 and tend to be in a stretched state, completely or partially in contact with the corresponding target tissue 5;

[0125] e) The surgeon determines whether the position of the stent 2 is ideal through the image. If it is ideal, the surgeon controls the detachable structure of the distal end of the inner core component 30 and the release head 233 on the stent 2 through the handle of the inner core component 30 to release the stent 2. After the stent 2 is fully released, it is completely attached to the target tissue 5 of the atrial septum. Fig.13When the placement position is not ideal, the delivery sheath 321 is slowly pushed to the distal end so that the stent 2 is completely placed in the delivery sheath 321, thereby realizing the recovery of the stent 2; and the stent 2 is subsequently implanted into the target tissue 5 through secondary adjustment.

[0126] Example 4

[0127] Based on Example 3, Example 4 is different from Example 3 in that: the stent system 1 containing a controllable release mechanism 23 includes a capture system 4, and the capture system 4 includes a snare 40, a capture inner sheath 41, and a capture outer sheath 42. Through the cooperation of the release hole 231, the release ring 232, the release head 233, the snare 40, and the capture inner sheath 41, the release head 233 protruding from the stent 2 can be placed in the capture inner sheath 41. Further, by using the capture outer sheath 42, the snare 40, the capture inner sheath 41, and the stent 2 can be placed in the lumen of the capture outer sheath 42, recovered and taken out of the body, thereby realizing the capture and recovery of the stent 2 in the case of unsatisfactory release effect or accidental drop, so compared with similar products on the market, the stent 2 of the present invention is safer and more recyclable. Preferably, the specification of the inner capture sheath 41 is 6Fr, and the specification of the outer capture sheath 42 is 8 to 24Fr. More preferably, the specification of the outer capture sheath 42 adapted to the stent 2 of the present invention is recommended to be 10Fr, 12Fr, or 14Fr.

[0128] When the stent 2 is completely released in the body, the image shows that the implantation position of the stent 2 is not ideal, especially when there is an emergency such as falling into the left atrium, right ventricle, or valve orifice, the stent 2 needs to be urgently captured and recovered. The specific process is as follows:

[0129] a) When the release ring 232 and the release head 233 are made of developing material, the release ring 232 and the release head 233 are visible, so that the operator can judge the position and state of the stent 2 through the image, and with the help of the image, firmly grasp the release head 233 through the snare 40 and lock the proximal end of the snare 40 with the capture inner sheath 41, as shown in FIG. Fig.14 As shown;

[0130] b) Keeping the position of the delivery sheath 321 or the capture sheath 42 unchanged, slowly withdraw the snare 40 toward the proximal end, so that the release head 233 and the distal end of the snare 40 are retracted into the delivery sheath 321 or the capture sheath 42, and continue to slowly withdraw the snare 40, so that the stent 2 is withdrawn as a whole into the delivery sheath 321 or the capture sheath 42, as shown in FIG. Fig.15 As shown;

[0131] c) withdrawing the delivery sheath 321 or the capture sheath 42, and withdrawing the snare 40 and the stent 2 out of the body, such as Fig.16 As shown, it can be easily captured and retrieved after complete release or accidental fall-off, thus ensuring higher safety and retrievability during and after surgery.

[0132] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A stent system with a controllable release mechanism, comprising an elastic stent and a delivery system for delivering the stent to a target position in the body. The stent is formed by a framework surrounded by support rods, and the stent includes a first support section, an intermediate support section, and a second support section. It is characterized in that the stent is a self-expanding structure. The first support section includes a controllable release mechanism, and the controllable release mechanism includes a release rod, release holes, a release ring, and a release head. The release holes include a first release hole and a last release hole; the release rod is located at the proximal end of the first support section and is fixedly connected to the corresponding support rod. The release holes are fixedly arranged at the proximal end of the release rod. The release ring sequentially penetrates through the release holes and forms a closed loop. The release ring forms a sliding connection with at least one of the release holes. The release head is connected to the release ring, and the release head is detachably connected to the delivery system; the stent has a first form and a second form that can be mutually converted. By pulling the release head, all the release holes approach each other and收拢, driving the stent to contract. Finally, the entire stent is linearly loaded or pulled into the delivery system, which is the first form; the second support section and the intermediate support section are restored to a preset shape in sequence. Subsequently, the release rod of the first support section is restored to a preset shape as the release ring relaxes. The fully expanded state after being completely released to the target position is the second form.

2. The support system according to claim 1, characterized in that: The first release hole is close to the release head and has the largest distance from the closed-loop contour formed by the distal ends of all the release rods.

3. The support system according to claim 2, characterized in that: The release holes include the first release hole, the second release hole, the third release hole, ... the last release hole, the first release hole is at the smallest distance from the central axis of the bracket, and the distances between the first release hole, the second release hole, the third release hole, ... the last release hole and the central axis of the bracket are defined as L1, L2, L2', L3, L3' ... L n-1 , L n-1 ', L n , among which L1, L2, L2', L3, L3'...L n-1 , L n-1 ', L n Satisfy the mathematical relationship: L1 <L n <L2<L3<……<L n-1 or L1 <L2<L3<……<L n-1 <L n , L2=L2', L3=L3'……L n-1 =L n-1 ', the centers of all the release holes are not on the same circle.

4. The support system according to claim 3, characterized in that: The number of the release holes is at least 4. The head and tail of the release ring both pass through the first release hole, so that in the second form, the position of the release head relative to the first release hole is limited. The last release hole includes a double-hole structure, and the release ring sequentially penetrates through the double-hole structure.

5. The support system according to claim 3, characterized in that: The lengths of the first release hole, the second release hole, the third release hole, ... the last release hole are respectively M1, M2, M3, ... n When the release ring is linear, the outer diameter of the release ring itself is M0, then M1, M2, M3...M n Satisfy the mathematical relationship: M1>2×M0, M2>3×M0, M3>3×M0…M n-1 >3×M0,M0 <M n ≤3×M0, 0.08mm≤M0≤1mm.

6. The support system according to claim 1, characterized in that: The proximal ends of every two adjacent release rods are joined and fixedly connected to form a release connecting piece. The distal end of the release connecting piece includes a joining point. The release holes are located on the release connecting piece. Except that the central axes of the first release hole and the last release hole pass through the corresponding joining points, the central axes of the remaining release holes do not pass through the corresponding joining points and are located on the side close to the release head; the release holes and the release ring are in an interpenetrating structure. For any one of the release holes, on the side close to the release head, the release ring is on top and the release hole is below; on the side far from the release head, the release ring is below and the release hole is above.

7. The support system according to claim 1, characterized in that: The central axis of the release hole forms an angle b with the plane where the proximal regions of the two adjacent release rods are located, satisfying: 0° < b ≤ 90°. The first release hole has the largest distance from the surface surrounded by the first support section.

8. The support system according to claim 1, characterized in that: The release head includes a release head head and a release head neck. The maximum dimension of the release head head is at least the maximum dimension of the release head neck or at least 4 times the wire diameter of the release ring. The central axis of the release head forms an angle γ with the plane surrounded by the support rods in the proximal region of the first support section, satisfying: 5° ≤ γ < 90°.

9. The support system according to claim 1, characterized in that: A release extension rod is fixedly connected to the proximal end of the first release hole, and an auxiliary release hole is provided at the proximal end of the release extension rod. Both the head and tail of the release ring pass through the auxiliary release hole. In the second form, the position of the release head relative to the auxiliary release hole is limited, and the auxiliary release hole is located between the first release hole and the inner wall of the middle support section.

10. The support system according to claim 6, characterized in that: The outer surfaces of all the release rods are wrapped with a winding body, and the winding body is wound at the release connecting piece to form the release hole.

11. The support system according to claim 10, characterized in that: The winding body is formed with a reinforcement structure, and the reinforcement structure is located on the release rod, so that the release connecting piece, the release hole and the release rod are fixedly connected and the relative position of the release hole on the release rod is limited.

12. The support system according to claim 1, characterized in that: The delivery system includes an inner core component, a middle layer component, and a catheter sheath component that can form relative axial movement. The inner core component is detachably connected to the release head. The distal region of the middle layer component is provided with a middle layer tube. The release ring and the release head can enter and exit the middle layer tube.

13. The support system according to claim 1, characterized in that: It also includes a capture system, which includes a snare, a capture inner sheath and a capture outer sheath. The release hole, the release ring, the release head, the snare and the capture inner sheath and / or the capture outer sheath cooperate with each other, so that the stent can be captured and taken out of the body.

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